Linear polyester polymers are widely known and have demonstrated utility in an ever-increasing number of applications. The most widely recognized polyester, poly(ethylene terephthalate) has been long established as the basis of fibers, films, molding plastics, and containers for liquids. Poly(butylene terephthalate) is also recognized as a molding plastic and molecular component of polyetherester thermoplastic block copolymer for elastomers. The alicyclic ring-containing polyester and copolymers thereof are also recognized for their fiber and plastics applications.
Conventional methods of preparing polyesters employ organic polymerization medium such as hydrocarbons and chlorinated hydrocarbons for solubilizing the monomers for polymerization. As organic solvents become a source of increasing environmental concern, there is a need for a method of preparing polyester which avoids the use of these organic solvents.
Conventional polyester polymerization techniques also possess the disadvantage of requiring vacuum separation techniques for the removal of condensates produced during polymerization. These vacuum separation techniques are typically expensive.
There remains a need in the art for a method of making polyester polymers which avoids the use of organic solvents and the need for expensive vacuum separation techniques for the recovery of condensates. In addition, there is a need in the art for a method of preparing polyester polymers with controlled morphologies and which permits the relatively easy separation of the polymer from the polymerization medium.